Research On The Multi-drive Cooperation Control Algorithm For A Long-distance Belt Conveyor

With the continuous development of modernization in manufacturing,agriculture,transportation,and other industries,the proportion of belt conveyors operating under special conditions such as long distance,large capacity,high belt speed,and large inclination angle are increasing.Due to the limitation of the belt material,the maximum tension that the conveyor belt could withstand cannot be increased indefinitely,resulting in a great limitation in the development of long-distance belt conveyors.The above problem can be solved by adding drives to the appropriate positions of the tail,middle and so on of the belt conveyor.However,the technical difficulty of multi-point drive lies in the collaboration between each drive and how to ensure the belt speed to be stable.Therefore,the characteristics of multi-point drive cooperative control for long-distance belt conveyors are investigated in the thesis.By theoretical research,co-simulation and experimental verification,the performance of multi-point driven belt conveyor cooperative control system is studied in the paper.Based on the previous research on multi-point drive of belt conveyor,the multi-point drive theory of the long-distance belt conveyor and the dynamic characteristics of the conveyor belt are analyzed.Combining the characteristics of the common soft starter of the belt conveyor,the direct torque control frequency conversion method is selected to realize the control of the conveyor operation,and the control principle is analyzed to establish the mathematical model and Simulink simulation model for the frequency converter.Meanwhile,based on the AMESim/Simulink joint simulation platform,the simulation model for the three-point driving system of the long-distance belt conveyor is established,and the correctness of the simulation models for the conveyor belt and the belt conveyor system were verified by the conveyor belt's tensile test and the conveyor system's verification experiments respectively.After comparing the performance of the head,middle and tail three-point driving system and the head and double intermediate three-point driving system,the improved master-slave control strategy is used to carry out cooperative control on the head,middle and tail three-point driving mode of the above-mentioned long-distance belt conveyor.The performance of the conveyor's speed,acceleration and tension are compared with the traditional constant voltage frequency ratio inverter control method.The joint simulation results show that:(1)When the conveying distance is 6 km,adding drives at the appropriate positions in the middle and tail of the belt conveyor could reasonably reduce the tension fluctuation in the starting process of the system,and also make the overall belt speed of the system more stable.(2)The performance of the head,middle and tail three-point driving system is significantly better than the head and double intermediate three-point driving system.(3)Compared with the traditional constant voltage frequency ratio frequency conversion control,the head,middle and tail three-point driving mode of the long-distance belt conveyor which is based on the direct torque control can better control the speed,acceleration and tension of the belt conveyor from start-up to steady operation.At the same time,the output power and the output torque of each drive motor are also significantly better.It can be seen from the above that the head,middle and tail three-point driving mode of long-distance belt conveyor based on the direct torque control could meet the requirements of the driving force change during the starting process,effectively reduce the tension at the start,which provides a theoretical support for the designing of the long-distance belt conveyor in the future.